The invention relates to a vacuum valve comprising a valve housing with first and second valve openings, which have parallel axes and are each enclosed by a valve seat, a first and a second valve plate, which can be adjusted between an open position, in which the valve plates free the respective valve opening, an intermediate position, in which the valve plates cover over the respective valve opening, but are raised up from the valve seat, and a closed position, in which the valve plates butt against the respective valve seat, and a carrying unit, which carries the valve plates and which has drive elements which are intended for adjusting the first and second valve plates between the intermediate position and the closed position and each comprise a cylinder, having at least one cylinder space, and at least one piston, which is arranged in the cylinder space and has a piston rod, which is connected to one of the valve plates.
WO 2011/096613 A1, KR 10-2010-0061214 and US 2006/0225811 A1 disclose vacuum valves having first and second valve plates which, in the closed state of the vacuum valve, close first and second valve openings of a valve housing. In the case of these vacuum valves, a carrying unit, which carries the valve plates, is fitted on at least one valve rod which can be displaced in the direction of its longitudinal axis. The displacement of the valve rod allows the valve plates to be adjusted between an open position, in which they free the respective valve opening, and an intermediate position, in which they cover over the respective valve opening, but are raised up from the valve seat. Piston/cylinder units, with the valve plates fitted on the piston rods thereof, are integrated in the panel-like or cuboidal carrying unit. The piston/cylinder units allow the valve plates to be adjusted between the intermediate position and a closed position, in which they close the respective valve opening.
U.S. Pat. No. 6,899,316 B2 discloses a vacuum valve in which a carrying unit carries a single valve plate. Piston/cylinder units, with the valve plate fitted on the piston rods thereof, are integrated, as drive elements for the valve plate, in the cuboidal carrying unit. The carrying unit is fitted on a valve rod, which can be adjusted in the direction of its longitudinal axis. A similar vacuum valve is known from common usage. In the case of the latter, the drive elements provided for the valve plate are, once again, piston/cylinder units, in this case fastened on the outside of the panel-like carrying unit. The piston rods of these piston/cylinder units have an enlarged head on the end side. These heads of the piston rods are retracted into undercut grooves provided in the valve plate. The longitudinal peripheries which delimit the respective groove on the surface of the valve plate thus form a receiving slot which allows the respective piston rod to be retracted in a piston-rod neck portion adjoining the head portion. In order to secure the heads in the grooves, use is made of fastening screws which are screwed into the piston rods through the valve plate. The valve plates are also connected to the drive elements of the carrying unit in an analogous manner in the case of the vacuum valve from KR 10/2010-0061214.
US 2004/0079915 A1 and U.S. Pat. No. 6,561,484 B2 disclose vacuum valves in which a valve plate and a supporting plate, located opposite, are carried by a carrying unit and can be adjusted in relation to the carrying unit by means of piston/cylinder units. In the closed state, the supporting plate is supported on the valve housing, in order to push the valve plate onto the valve seat.
In the case of the vacuum valve which is known from US 2008/0066811 A1, a carrying unit, on which first and second valve plates are fitted on opposite sides, is displaced by means of push rods, in order to push either the first valve plate or the second valve plate onto the valve seat. The push rods are actuated by piston/cylinder units, which are arranged on the valve housing.
US 2011/0095218 A1 discloses a vacuum valve in which first and second valve plates are fastened in a non-movable manner on a carrying unit. The carrying unit is adjusted by means of a valve rod in order for each of the valve plates to be pushed alternately onto one of the valve seats. The valve plates are pushed onto the carrying unit via guides, wherein a protrusion of the carrying unit engages in an undercut groove of the respective valve plate.